From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Thu, 27 Nov 2008 10:05:55 +0000 (+0100)
Subject: [S390] fix system call parameter functions.
X-Git-Tag: v2.6.28-rc7~54^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59da21398e680e8100625d689c8bebee6a139e93;p=pandora-kernel.git

[S390] fix system call parameter functions.

syscall_get_nr() currently returns a valid result only if the call
chain of the traced process includes do_syscall_trace_enter(). But
collect_syscall() can be called for any sleeping task, the result of
syscall_get_nr() in general is completely bogus.

To make syscall_get_nr() work for any sleeping task the traps field
in pt_regs is replace with svcnr - the system call number the process
is executing. If svcnr == 0 the process is not on a system call path.

The syscall_get_arguments and syscall_set_arguments use regs->gprs[2]
for the first system call parameter. This is incorrect since gprs[2]
may have been overwritten with the system call number if the call
chain includes do_syscall_trace_enter. Use regs->orig_gprs2 instead.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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